Middle East Respiratory Syndrome coronavirus (MERS-CoV) has recently emerged as causative agent of severe respiratory disease in humans. Two hundred and six cases of MERS-CoV infection have been confirmed to date, including 71 deaths. Most infections were geographically linked to the Middle East, but cases also occurred in the UK, Germany, France, Italy and Spain. Dromedary camels are likely the reservoir for MERS-CoV virus. The MERS-CoV spike (S) protein, a characteristic structural component of the viral envelope, is considered a key target of vaccines against coronavirus infection, as we and other have previously demonstrated for severe acute respiratory syndrome (SARS) infection. As an initial attempt to develop a MERS-CoV vaccine, we constructed two recombinant adenoviral vectors encoding the full-length MERS-CoV spike (S) protein (Ad5.MERS-S) and the S1 domain of S protein (Ad5.MERS-S1), which mediates binding to the dipeptidyl peptidase 4, which serves as the host cell receptor of MERS-CoV. The safety profile and the growth characteristics of adenoviral-based vaccines make them suitable MERS-CoV vaccine candidates for preclinical testing. Over the past 15 years, we have demonstrated the extraordinary efficacy of adenoviral vaccine platform in eliciting T and B cell-specific responses to the desired antigens and have been involved in developing promising SARS, influenza and RSV vaccines. Here, we hypothesize that subcutaneous (SQ) and/or intranasal administration (IN) of Ad5.MERS vaccines will elicit MERS-CoV-specific immunity, which will lead to the protection of immunized animals. Ultimately our goal is to develop a veterinary vaccine to target dromedary camels. We will test our hypothesis with four specific aims which will: a) test the immunogenicity of the Ad5.MERS vaccine in a mouse model; b) define the optimal immunization schedule and route of administration; c) establish a MERS-CoV challenge model and d) determine the ability of the selected Ad5.MERS vaccine to protect animal from MERS-CoV challenge in the absence of enhanced disease.